Ductility

A measure of the degree of plastic deformation at fracture.

Most metals are ductile. Ductile materials have high tensile strength.

Percentage elongation

$$\frac{l_f - l_0}{l_0} \times 100$$

Percentage reduction in area

$$\frac{A_0 - A_f}{A_0} \times 100$$

Brittle

A material that experiences very little or no plastic deformation.

Brittleness order: Ionic bonds > Covalent bonds > Metallic bonds

Malleability

Ability of a material to undergo plastic deformation under compression.

Note

All ductile materials are malleable. Converse is not true.

Ductility & Brittleness

Depends on:

• Composition of the material
• Temperature